Off-road vehicles such as articulated four wheel drive loaders, for example, are often equipped with final drives that employ a planetary transmission for speed reduction and an oil cooled brake pack to which both park brake and service brake forces are selectively applied to respectively establish park brake and service brake engage conditions. Often these final drives are not arranged so as to be easily serviced or assembled or so as to have a relatively simple passage arrangement for routing cooling and/or lubricating fluid to the brake discs and bearings subject to relatively high input speeds, i.e., speeds that occur upstream of the second stage of the planetary transmission.
U.S. Pat. No. 4,142,615 discloses a vehicle final drive arrangement including a spindle rotatably supporting a wheel hub and having a disc brake pack mounted within an outer end region thereof with a reaction plate being mounted at the outer end of the spindle. Cooling and lubrication fluid is contained within a chamber formed by the wheel hub, a planet carrier fixed to an outer end of the hub and a cap fixed to the planet carrier, this fluid having to exist at a certain level within the chamber in order for there to be sufficient fluid available for the planet carrier and gears to enter the fluid and splash or slop cooling and lubricating fluid around the moving parts of the planetary reduction gear train. Cooling and lubricating fluid existing at the center of the gear train is pumped by the meshing teeth of the sun gear and planet gears so that it flows through a passage extending between the teeth and the inner part of the disc brake pack so that adequate fluid is available for cooling the disc brake pack.